Determination of melatonin in grape skin by liquid chromatography - mass spectrometry

GONZALEZ, CARINA VERONICA; BOCCALANDRO, HERNÁN ESTEBAN; QUIROGA, MARIELA ANDREA; WUNDERLIN, DANIEL; SILVA, MARÍA FERNANDA

Mendoza

Congreso; XXVI Reunión Científica Anual Sociedad de Biología de Cuyo; 2008

Sociedad de Biología de Cuyo de Mendoza

Melatonin (MT), the often called ‘hormone of darkness’ is a ubiquitous molecule widely distributed in nature, produced by unicellular organisms, plants, fungi and animals. It plays a significant role in regulation of physiological cycles, as its synthesis is highly dependant of light exposure conditions. In addition to the hormonal activity, it has been proven that is an effective antioxidant, presents inhibitory effects on some cancer forms and shows beneficial effects on neuronal disorders. The late discover of MT in plants has opened up a new field of knowledge in the food and nutritional sciences. The latter offers an interesting perspective associated to the plethora of health benefits related to the moderate consumption of red wine. The purpose of this study was to develop a simple, accurate, fast, sensitive and reliable LC-MS/MS methodology for the melatonin determination in plant tissues. We analyzed grape skin of Vitis vinifera cv Malbec grown in Tupungato – Mendoza, sampled at 3 h intervals during a whole day at the end of April, in order to asses the daily rhythm of MT in this cultivar near the commercial harvest. Excellent linearity was observed between peak area and concentration in the range from 7 to 300 ng.g-1 of berry skin dry weight. Our findings demonstrated changes in MT contents during the day (concentrations ranging from 10 to 180 ng.g-1 dry weight), with a strong peak at 9:30 am.